Your major does not matter because every cadet enters under the premise they will serve ADAF in some capacity. Rated/non-rated occurs when you are a junior in college, and that is when eyesight becomes a factor.
You just have to go through the process. Please understand that this is not just about you. It becomes an AF thing from multiple aspects. Health costs being one of them. Deployment being another.
I get your intention is to go nursing, and they know this, but the reality is the AF is slowly replacing nursing staff with civilians. Most AF bases do not have surgical units anymore, only the big bases like Brooks, Ramstein, etc have that option, otherwise any surgery that is needed, even a military member is sent off base for surgery.
~ Honestly, I can't think of many AFB that have surgical units. DS1 is an O2 pilot (14 winging) and I can tell you the 3 bases he has been stationed at so far did not have surgical units, heck they don't even have maternity wards, and their ER closes at 4. This has been true for years upon years...think since 2000.
Unfortunately, the military is getting out of the health care business, and now it is more typical to be referred out to a civilian Tri-Care provider. Sorry if that is disheartening, but that is the future.
Best of luck.